make log_rotation.sh safer

log_rotation.sh

@@ -1,20 +1,20 @@
 #!/bin/sh
 
-if [ "$1" = "" ]; then
-	/bin/echo "no file"	
+if [ "$1" == "" ]; then
+	echo "no file"
 elif [ "$1" = "/tmp/rsyslog/root_file" ]; then
 	/bin/rm -f "$1"
 else
-	new_file=$1"_"`/bin/date '+20%y_%m_%d'`
+	new_file="${1}_$(/bin/date '+20%y_%m_%d')"
 	i=0
-	test_file=$new_file
-	while [ -f $test_file ]
+	test_file="$new_file"
+	while [ -f "$test_file" ]
 	do
 		i=$(($i+1))
-		test_file=$new_file"."$i
+		test_file="${new_file}.${i}"
 	done
 	
-	/bin/mv -f "$1" $test_file
+	/bin/mv -f "$1" "$test_file"
 fi
 
 exit 0